CSB Issues Update on Fatal Explosion at Nebraska Biofuels Facility

The U.S. Chemical Safety and Hazard Investigation Board (CSB) provided an update this week on the agency’s ongoing investigation into the fatal July 29, 2025 explosion and fire at the Horizon Biofuels facility in Fremont, Nebraska.

The incident resulted in the deaths of three people — an operator and his two young daughters, ages 8 and 12.

“This terrible tragedy should not have happened,” said CSB Chairperson Steve Owens. “Preliminary evidence points to a combustible wood dust explosion, a well-known – and completely avoidable — hazard in wood processing.”

The incident occurred at the Horizon Biofuels facility shortly before noon on July 29, following a sudden release of dust or smoke from the tower, quickly followed by flames and a much-larger, major blast that caused significant structural damage.

The day shift operator, who had brought his two young daughters to work with him, was trapped inside the collapsed structure and died. His two daughters, who were in the break room at the facility, also were killed in the explosion. Emergency responders were unable to enter the unstable, burning building until the following day, when they recovered the bodies of the three fatally injured people.

The explosion caused severe damage within the facility, affected vehicles on-site and nearby, and led to road closures that disrupted local businesses for several days. Several fires also occurred at the facility and combustible material at the facility has continued to smolder for more than a month.

The CSB previously has investigated a number of combustible dust incidents across industries. Additionally, in 2006 the CSB issued a major study of combustible dust incidents involving 281 dust explosions that resulted in 119 deaths and 718 injuries.